Climate averages 1991–2020

Pematangsiantar weather
by month.

See how the year changes. June has the highest average daily maximum; February has the lowest average monthly rainfall.

Long-term climate patterns, not a forecast for a particular trip.

Warmest month 28.3°C June, average high
Coolest month 20.2°C January, average low
Wettest month 375 mm October, monthly total
Driest month 190 mm February, monthly total
The year at a glance · average highYear overview

Across the year Pematangsiantar averages a daytime high of 27.4°C and a nighttime low of 20.7°C, with about 3,303 mm of rain on roughly 338 days. June is the warmest month (average high 28.3°C) and December the coolest (26.3°C). October is the wettest month with 375 mm; February is the driest with 190 mm.

The annual picture

A year in Pematangsiantar

30-year average
Average highAverage low°C
Average daily high and low temperatures by month The same values are available in the monthly table below. Lines show mean daily maxima and minima, not a forecast interval. 1520253035 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly rainfall

Average total · mm
Average monthly rainfall totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 4000

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Pematangsiantar climate table

1991–2020
Monthly climate averages for Pematangsiantar, 1991–2020
MonthAverage highHigh / lowAverage lowRainfall mm/monthRain days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 26.6°C20.2°C20.2°C24027.912.012 h
February 27.1°C20.2°C20.2°C19024.312.012 h
March 27.8°C20.7°C20.7°C21726.412.112 h
April 27.9°C21.0°C21.0°C24928.612.212 h
May 28.2°C21.3°C21.3°C26529.212.312 h
June 28.3°C21.1°C21.1°C23127.112.312 h
July 28.1°C20.8°C20.8°C23626.712.312 h
August 27.9°C20.7°C20.7°C27428.712.212 h
September 27.5°C20.6°C20.6°C36129.412.112 h
October 27.1°C20.6°C20.6°C37530.212.112 h
November 26.6°C20.6°C20.6°C35129.412.012 h
December 26.3°C20.5°C20.5°C31529.612.012 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

Nearby cities

Distance from Pematangsiantar

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits
What do the high and low temperatures mean?

We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.

How is a rain day counted?

A local calendar day (standard time, UTC+7, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.

Where do the numbers come from?

ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 3.00°, 99.10° (6 km from the city centre), adjusted down by 0.5°C for the difference between the city's elevation (388 m) and the cell's (304 m). Rain comes from the 0.25° cell at 3.00°, 99.00°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.

Does this page show sunshine, humidity or sea temperature?

No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.